Fabrication of hollow [formula omitted] spheres (x = 0.0, 0.5, 1.0) as high-performance electromagnetic absorber material

Abstract

Hollow Ni1-xZnxFe2O4 spheres (x = 0.0, 0.5, 1.0) were synthesized using the solvothermal process. All samples were subjected to X-ray diffraction analysis to determine their crystal structure. Raman spectroscopy was used to investigate the vibrational properties of the material. While field emission scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy were employed to confirm the morphologies and distribution of elements. The prepared hollow spheres exhibited improved magnetic properties for NiFe2O4 and ZnFe2O4 samples, while Ni0.5Zn0.5Fe2O4 showed a relatively smaller value. This variation in magnetic properties is discussed in terms of mixed cation distribution and the relatively large specific surface area of the hollow spheres. The complex permittivity and permeability were measured at microwave frequencies (2 – 11 GHz) using cavity resonator approaches. The Ni0.5Zn0.5Fe2O4 sample exhibited a high attenuation constant, better impedance matching, and a high reflection loss value of −20.6 dB at 5.4 GHz for a modeled thickness of 3 mm when dispersed in paraffin wax. Furthermore, an investigation of the quarter wavelength model for best matching thickness reveals a high degree of agreement between experimental and simulated absorber thickness (tm) values. Overall, the findings demonstrate that hollow structures are more efficient than their bulk counterparts. This work shows that hollowNi0.5Zn0.5Fe2O4 spheresare a potential candidate for an enhanced and dominant microwave absorption field.